Description: (Taken directly from the application) The objectives of this Core Laboratory are: 1. To make available to cooperating investigators an array of specialized measurements for estimating body composition in human subjects and in laboratory animals. 2. To provide investigators with a variety of specialized physical performance measures for evaluating human subjects. 3. To provide investigators with the resources needed to make specialized measurements of energy expenditure and balance in human subjects and in laboratory animals. 4. To make available to investigators the techniques needed to assess the composition of a variety of foods. 5. To provide a setting in which instruction in body composition, physical performance, and energy expenditure methodology can be offered to students, postdoctoral research fellows, and other interested scientists. 6. To sponsor and participate in the conduct of periodic seminars on "state-of-the-art" body composition, physical performance, and energy expenditure methods, with ultimate emphasis on those of greatest relevance to the problem of human obesity.